cmake COMPILER_RT_HAS_WD4291_FLAG examples

Lewuathe/mlir-hello thirdparty/llvm-project/compiler-rt/cmake/config-ix.cmake :159 

check_cxx_compiler_flag(/wd4291 COMPILER_RT_HAS_WD4291_FLAG)

trailofbits/polytracker polytracker/src/compiler-rt/cmake/config-ix.cmake :115 

check_cxx_compiler_flag(/wd4291 COMPILER_RT_HAS_WD4291_FLAG)

CTSRD-CHERI/cheribsd contrib/subrepo-cheri-compiler-rt/cmake/config-ix.cmake :136 

check_cxx_compiler_flag(/wd4291 COMPILER_RT_HAS_WD4291_FLAG)